Medical solution container

ABSTRACT

This invention relates to a container for medical solution comprising a port portion (12), a shoulder portion (13) and a flat body portion (14), and is characterized in that side peripheral areas (15) and tail end peripheral area (16) are welded by a sealer (101). This configuration allows the container to flatten as the contained medical solution drains, thus the solution is completely drained and does not remain in the container. 
     The same advantage can be expected when the wall thickness of the container in the side peripheral areas (15) and the tail end peripheral area (16) are made to be thinner than one in the central area of the body portion instead of welding the side peripheral area (15) or the tail end peripheral area (16).

This is a divisional of copending application(s) Ser. No. 07/267,717,filed Nov. 3, 1988, U.S. Pat. No. 5,023,110, which is a continuation of07/027,228 filed as PCT/JP86/00029 on Jan. 13, 1986, now abandoned.

TECHNICAL FIELD

This invention relates to a container for medical solution and themethod of making the same. It especially relates to the container formedical solution for a closed injection system which is easilycollapsible and is not damaged by autoclave sterilization, and themethod of making the same.

BACKGROUND ARTS

A closed system has been recently used in medicine, to prevent thecontained solution, such as infusion therapy, from contact with theatmosphere. Configuration and materials of the container for medicalsolution for a closed injection system must be considered such that itis soft enough to drain the contained solution with gravity pressure.This kind of solution container also must be able to endure autoclavesterilization for the contained solution.

Further, the container is preferably made of transparent material sothat the level of the solution can be checked easily and particle mattercan be inspected from the outside. In order to obtain these objectives,soft polyvinyl chloride or ethylene-vinyl acetate copolymer have beenextensively utilized as the materials of the conventional solutioncontainer. Soft polyvinyl chloride poses a health problem for humanbody, where a great amount of plasticizer may dissolve into thecontained solution. On the other hand, ethylene-vinyl acetate copolymermay dissolve into the contained solution as the result of deacetating atforming, and does not have any heat-resistance during autoclavesterilization.

Therefore, ethylene-vinyl acetate copolymer must be cross-linked byradiation such as gamma ray in order to get specified heat-resistance,which causes an additional process in producing containers. In additionto this, the radiation decomposes ethylene-vinyl acetate copolymer toproduce organic substances such as acetone, acetaldehyde, acetic acid,isobutane, n-butane, butadiene, propylene etc., and therefore airventilation is required to exhaust these organic substances, which addsan additional process in producing containers and makes it difficult tokeep the work area safe.

Polyolefin, polyamide, polyurethane etc., being much safer to use andhaving superior properties, have been considered for the materials ofcontainers for medical solution, especially polyolefin has been seen asthe most adequate one because of its low price. However, it wasextremely difficult to produce a desired container for medical solutionwith these materials; polyolefin, polyamide, polyurethane etc. Aspolyolefin, polyamide and polyurethane have lower dielectric loss thanpolyvinyl chloride or ethylene-vinyl acetate copolymer, high frequencyelectric fields do not produce enough heat to dissolve the material,thereby these polymers are not available for high frequency sealing asin the case of polyvinyl chloride. Accordingly, for example, when acontainer for medical solution is made of polyolefin tube which isproduced by inflation forming, or is made of two pieces of polyolefinsheet, the open end of the tube itself or the specified part coveredwith an additional sheet must be welded by impulse sealing or heatsealing. However, it is difficult to weld complicated structures withimpulse sealing, in contrast to high frequency sealing, and alsodifficult to weld the materials with different thickness, on the surfaceof structures such as pipes, because impulse sealing and heat sealinginduce heat to the materials from the outside, thus these ways ofsealing make it difficult to form a small port on the top of a containerfor medical solution.

On the other hand, blow molding containers for medical solution madefrom polyolefin may be considered, in which the small port portion isintegral with the body portion. However, the container for medicalsolution made by this method has the problem where the containedsolution can not be completely drained, because the material is not softenough, the body portion is cylindrical, the wall thickness of the bodyportion is almost uniform, and the wall thickness of the body near theperipheral area in tail end is greater than the center portion.Therefore, the container for medical solution made by the conventionalblow molding is not available for a closed system. No container formedical solution suitable for containers for infusion fluid or the likehas been developed until now by these methods.

The object of this invention is to provide a new container for medicalsolution and the method of making the same.

Another object of this invention is to also provide a container formedical solution made from organic polymers, suitable for containers forinfusion fluid or the like, and the method of making the same.

Further object of this invention is to provide a container for medicalsolution made from organic polymers, which can drain the containedsolution easily and completely, and the method of making the same.

DISCLOSURE OF THE INVENTION

This invention relates to the container for medical solution made fromorganic polymers, comprising of the integrated port portion, theshoulder portion, and the flat body, wherein forming the container byblow molding and welding its side peripheral areas and/or tail endperipheral area make it easy to completely drain the contained solution.

The further preferred embodiment is the container for medical solutionmade from polyolefin, comprising of the port portion, the shoulderportion, and the flat body portion, wherein the density of polyolefin is0.915-0.930 g/cm³ and Olsen stiffness is under 4000 kg/cm², the wallthickness of side peripheral areas and/or tail end peripheral area ofthe body portion is thinner than one of the central portion, and theshorter length of the shoulder portion does not exceed 30 mm. Thiscontainer is suitable for a closed system, as the pressure differencebetween the inside and the outside in the body makes it easy for thebody portion to collapse.

This invention, also, discloses the method of making the container formedical solution characterized in that after a blow molding productcomprising of the integral port, shoulder and body is formed fromorganic polymer, at least one side of side peripheral areas and/or tailend peripheral area of the blow molding product is welded.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1(a) is a front view in the first embodiment of the container formedical solution of this invention.

FIG. 1(b) is a transverse sectional view taken along line 1B--1B of FIG.1(a).

FIG. 1(c) is a top view in the first embodiment of the container formedical solution of this invention.

FIG. 2(a) is a front view in the second embodiment of the blow moldingproduct for making the container for medical solution of this invention,and FIG. 2(b) is the side view.

FIGS. 3 and 4 are transverse sectional views in each process showing themethod of making said blow molding product.

FIG. 5(a) is a front view in the third embodiment of the container formedical solution of this invention.

FIG. 5(b) is a transverse sectional view taken along line 5B--5B of FIG.5(a).

FIG. 6(a) is a front view in the improved third embodiment of thecontainer for medical solution of this invention.

FIG. 6(b) is a transverse sectional view taken along line 6B--6B of FIG.6(a).

FIG. 7 is a sectional side view in the fourth embodiment of thisinvention.

FIG. 8 is a figure showing how to use the container for medical solutionof this invention.

BEST MODE FOR CARRYING OUT THE INVENTION

The invention will be explained with figures as follows.

As the first embodiment shown in FIGS. 1(a), (b) and (c), the containerfor medical solution of the invention made from organic polymers, is ablow molding product in which a small port 12, shoulder 13, and body 14are formed as an integral, and side peripheral areas 15 and tail endperipheral area 16 of body 14 are welded. This configuration allows theinside surfaces of body 14, to contact each other in the whole and thusresulting in the confined space of the container when the solution isnot contained or when drained. Therefore, almost no solution remains inthe container when this container for medical solution 11 is used as inFIG. 8. Even though either welding of side peripheral areas 15 or tailend peripheral area 16 is effective, both welding of side peripheralareas 15 and tail end peripheral area 16 are further preferable.

Although many kinds of organic polymers are available for the materialof the container for medical solution 11 of the invention, polyolefin ispreferable. Polyolefin suitable for use in the invention includes lowdensity polyethylene, polypropylene and the like having a flexuralelastic modules not greater than 4000 kg/cm². Further preferablepolyolefin includes low density polyethylene having a density of0.915-0.939 g/cm³.

Linear low density polyethylene; LLDPE different from general lowdensity polyethylene is further preferable material. LLDPE is acopolymer of ethylene and α-olefin; α-olefin includes butane-1 of whichcarbon number is 4, methylpentane-1 of which carbon number is 6, octaneof which carbon number is 8, and the like. Further preferred materialfor the container for medical solution is LLDPE of which α-olefin is 4methylpentane-1 and octane-1.

LLDPE in which α-olefin is 4 methylpentane-1 and octane-1, being soft,transparent and durable, is suitable for the material of the containerfor medical solution.

Another suitable material is polymer mixture of 50-90 wt % LLDPE and10-50 wt % block copolymer which is contrived from saturatedintermediate block consisting of conjugated diene copolymer units, andboth-end blocks consisting of styrene unit.

The preferable polymer composition of said polymer is that LLDPE isbetween 50 and 90 wt % and block copolymer is between 10 and 50 wt %.Block copolymer of less than 10 wt % can not soften copolymer, and oneof greater than 50 wt % makes it difficult to form the container,especially in case of blow molding. Therefore the most preferablecomposition is such that LLDPE is between 60 and 80 wt % and blockcopolymer is between 20 and 40 wt %.

Minor axis, indicated a in FIG. 1(c), of oval shoulder portion 13connected to the small diameter port 12 of the container for medicalsolution 11, is preferred to be not greater than 30 mm. If the minoraxis a of shoulder 13 is over 30 mm, the inside surfaces of the bodywill almost not contact when the contained solution drained. It resultsin a relatively large amount of solution remaining in the containergoing to waste without draining, as shown in the following table.

This table shows remaining solution in the container when the major axislength b is respectively 100 mm, 120 mm, 150 mm and minor axis length achanges from 15 mm to 45 mm. It is apparent that the remaining solutionincreases drastically, independent of the length b of major axis, whenthe minor axis length a is over 30 mm.

    ______________________________________                                        Remaining Solution (ml)                                                                    the length b of major axix                                       the length a of minor axix                                                                   100 mm     120 mm   150 mm                                     ______________________________________                                        15 mm          15         18       20                                         20 mm          25         30       40                                         25 mm          40         50       60                                         30 mm          60         70       85                                         35 mm          85         100      120                                        40 mm          110        130      160                                        45 mm          140        165      200                                        ______________________________________                                    

Providing the protruding portion 19 on central area of body 14 from thetop to the bottom, allows the remaining solution to be easily recognizedwhen air is introduced into the space of the protruding portion 19.

All air within the container for medical solution is confined to thespace of protruded portion 19 after draining the solution, hence the airconfined to the space can not go out unless special suction oradditional pressure to the container is given. Therefore, there is nodanger of air contamination within the container for medical solutionleaving the container and entering into a human body during normalinfusion therapy.

The preferred thickness of the container for medical solution 11 of thisinvention is 1-4 mm., preferably 1.5-3 mm, at port 12, and 0.05-0.5 mm,preferably 0.1-0.3 mm at body 14. If the thickness of the body wall isless than 0.05 mm, the container for medical solution will be fragile,thereby becoming unsafe for use as a container for medical solution. Onthe other hand, if its thickness is over 0.5 mm, the softness will belost and body 14 will be too hard to collapse, which causes a largeamount of solution to remain in the container. The second embodiment,the way of making the container for medical solution of this inventionhaving the aforementioned configuration, will be explained as follows.Blow molding product 31 made from organic polymer, comprising a smallport 32 on the top, shoulder 33 and body 34, in FIGS. 2(a) and (b) isproduced by blow molding in a unit. It is desirable that body 34 isformed evenly as possible. Due to this configuration, the sideperipheral areas and/or the tail end peripheral area can be easilyheated while the entire body of blow molding product 31 is flatlycollapsed, and also the container can be easily collapsed as thesolution is drained.

Body 34 of blow molding product 31, produced in the aforementioned way,is secondly pressed by pressing apparatus 101 as shown in FIG. 3. Thensealer 102 heats and welds side peripheral areas 40 and/or tail end area41 while body 34 is pressed as shown in FIG. 3. In this process, theextra portion of side peripheral areas 40 and/or tail end area 41, meltdown during heating. Alternatively, as shown in FIG. 4, cutter 103 cutsoff the undesired part of side peripheral areas 40 and/or tail end area41 after welding thereof thereby obtaining the completed container formedical solution 11. Available sealer 103 includes one used for heatsealing method, one used for impulse sealing method or the like,depending on the material adopted for the container for medicalsolution.

Tail end area 41, not shown in FIGS. 3 and 4, is similar to peripheralareas 40. Side peripheral areas 15 and tail end area 16 of the containerfor medical solution, obtained in the aforementioned steps, correspondrespectively to side peripheral areas 40 and tail end area 41 of blowmolding product 31.

The third embodiment of the container for the medical solution of theinvention is shown in FIGS. 5(a) and (b). This container for medicalsolution 71 is a blow molding product made from polyolefin, comprisingsmall port 72 on the top, body 73 adjacent to port 72 and hanger member74 provided on the lower portion of body 73. Providing possible flatnesson body 73 and the condition that minor axis of shoulder 79 is not over30 mm, make body 73 collapsible.

In addition, as the wall thickness of body 73 is thinner in sideperipheral areas 76 and/or tail end area 77 than in central portion 75,side peripheral areas 76 and/or tail end area 77 become more collapsibleand inside surfaces of central portion 75 easily contact each other.Therefore the container in the third embodiment even if side peripheralareas 76 or tail end area 77 is not welded, can drain much more solutionthan the one in the first embodiment. In the further preferredcontainer, as shown in FIGS. 6(a) and (b), for the improved thirdembodiment of the container for medical solution of this invention, sideperipheral areas 88 and/or tail end area 84 is welded (welding sideperipheral areas are not shown in FIGS. 6(a) and (b)), thus decreasingthe remaining solution in the container after draining. The material ofthe container for medical solution 71 or 81 of this embodiment ispolyolefin having a density of 0.91 to 0.930 g/cm³ and Olsen stiffnessbelow 4000 kg/cm². If polyolefin with a density over 0.930 g/cm³ orOlsen stiffness over 4000 kg/cm² is used for the solution container, itwill become hard and non-collapsible, thus not draining the solutionsmoothly. The aforementioned LLDPE is preferable for polyolefin.

The wall thickness in the body of the container for medical solution 71of the embodiment is 0.05-0.35 mm, preferably 0.1-0.3 mm. The wallthickness around central portion 75, further, prefers to be 0.2-0.3 mm,and side preferential areas 76 and/or tail end area 77 is preferablythinner than the central portion being 0.1-0.2 mm.

FIG. 7 shows the third embodiment of the container for medical solutionof the invention. Organic polymer 832 different from the material..ofthe container body 831 laminates the inside wall of the solutioncontainer. The material of laminated layer 832 includes polyolefin,nylon, polyurethane or the like of which composition does not dissolveat high temperatures. When the body 831 of the container for medicalsolution is made from inexpensive organic polymer such as polyvinylchloride, laminated layer 832 prevents plasticizer in polyvinyl chloridefrom dissolving into the solution at high-temperatures. Accordingly,this embodiment allows inexpensive organic polymer to be available forthe material of the container body, and makes it possible to reduceproduction price.

FIG. 8 shows the use of the container for medical solution of theinvention. The container is hung on hanger 281 with hanger member 26,and needle 202 is connected to solution administration set 201, thenpenetrated into the solution container through cap 221. Dotted lines inFIG. 8 show the the container filled with the solution. As the solutionis drained, the container flexes into a flat configuration. Therefore,the container of the invention does not permit the solution to contactwith the air, as in the case of a conventional container, and allows thesolution to almost completely drain out of the container.

Examples of the embodiments of the invention will be explained asfollows.

EXAMPLE 1

A blow molding product shown in FIGS. 2(a) and (b) was prepared by blowmolding of linear low density polyethylene (available under the tradedesignation "Ultzex" from Mitsui Petrochemical Industries, Ltd. having adensity of 0.93 g/cm³ and Olsen stiffness of 3500 kg/cm²). The wallthickness in central area of the body and side peripheral areas of theblow molding product was 250 m. The transverse cross section was ovalwith 120 mm major axis and with 15 mm minor axis.

As shown in FIG. 3, with the side peripheral areas and tail endperipheral areas of the blow molding product contacting each other bypressing the blow molding product, the heat sealer 101 heated and weldedthese parts for about 5 seconds, at 150° C., under 4 kg/cm².

Then the undesired portion 40 was cut off, and the container for medicalsolution was completed by providing hang member 16.

After the container was filled with 550 ml water, the port of thecontainer was sealed with linear low density polyethylene film, and thena rubber plug was placed on it.

Sterilizing the parenteral solution container for 40 minutes at 115° C.with autoclaving did not cause any significant deformation.

Measurement of the draining amount vs time with the conventionalinfusion therapy as shown in FIG. 8 in which needle 202 was penetratedthrough the port, the distance between the port and the needle for ahuman body was 70 cm, and the draining rate of solution was adjusted toabout 50 ml/minute with a clamp, proved that the draining amount wasalmost proportional to time. There was only 3 ml remaining in thecontainer after draining.

However, in the case of the container made from linear low densitypolyethylene (available under the trade designation "MORETEC" fromIdemitsu Petrochemical Co., Ltd. having a density of 0.935 g/cm³ andOlsen stiffness of 4600 kg/cm²), in the same method of this example, theremaining amount of the solution resulted in a greater value or 60 mlunder the same measurement conditions as the above.

EXAMPLE 2

A blow molding product shown in FIGS. 5(a) and (b) was prepared by blowmolding of linear density polyethylene (available under the tradedesignation "MORETEC" from Idemitsu Petrochemical Co., Ltd. having adensity of 0.920 g/cm³, Olsen stiffness of 2400 kg/cm²). The wallthickness in central area of the body of the blow molding product was300 m, and one of the side peripheral areas and the tail end peripheralarea was 150 m. The transverse cross section was oval with 120 mm majoraxis and with 15 mm minor axis. This blow molding product was thecontainer for medical solution itself without any other process.

After the container was filled with 550 ml water, the port of thecontainer was sealed with linear low density polyethylene film, and thena rubber plug was placed on it.

Sterilizing the parenteral solution container for 40 minutes at 115° C.by autoclaving did not cause any significant deformation.

Measurement of the draining amount vs time with the conventionalinfusion therapy as shown in FIG. 8 in which needle 202 was penetratedthrough the port, the distance between the port and the needle for ahuman body was 70 cm, and the draining rate of solution was adjusted toabout 50 ml/minute with a clamp, proved that the draining amount wasalmost proportional to time. There was only 7 ml remaining in thecontainer after draining.

However, in the case of the container made from linear low densitypolyethylene (available under the trade designation "MORETEC" fromIdemitsu Petrochemical Co., Ltd. having a density of 0.935 g/cm³ andOlsen stiffness of 4600 kg/cm²), in the same method of this example, theremaining amount of the solution resulted in a greater value or 60 mlunder the same measurement conditions as the above.

EXAMPLE 3

A blow molding product shown in FIGS. 5(a) and (b) was prepared by blowmolding of linear low density polyethylene (available under the tradedesignation "MORETEC" from Idemitsu Petrochemical Industries, Ltd.having a density of 0.92 g/cm³, Olsen stiffness of 2400 kg/cm²). Thewall thickness in central area of the body was 250 μm, and one of theside peripheral areas and the tail end peripheral area of the blowmolding product was 150 μm. The transverse cross section was oval with120 mm major axis and with 15 mm minor axis.

As shown in FIG. 3, with the condition that side peripheral areas andtail end peripheral area of the blow molding product were contactingeach other by pressing the blow molding product, the heat sealer 101heated and welded these parts for about 5 seconds, at 150° C., under 4kg/cm². Then the undesired portion was cut off, and the container formedical solution 81 was completed by providing hang member 85.

After the container was filled with 550 ml water, the port of thecontainer was sealed with linear low density polyethylene film, and thena rubber plug was placed on it.

Sterilizing the parenteral solution container for 40 minutes at 115° C.with autoclaving did not cause any significant deformation.

Measurement of draining amount vs time with the conventional infusiontherapy as shown in FIG. 8 in which needle 202 was penetrated throughthe port, the distance between the port and the needle for a human bodywas 70 cm, and the draining rate of solution was adjusted to about 50ml/minute with a clamp, proved that the draining amount was almostproportional to time. There was only 5 ml remaining in the containerafter draining.

However, in the case of the container made from linear low densitypolyethylene (available under the trade designation "MORETEC" fromIdemitsu Petrochemical Co., Ltd. with a density of 0.935 g/cm³ and Olsenstiffness of 4600 kg/cm²), in the same method of this example, theremaining amount of the solution resulted in a greater value or 55 mlunder the same measurement condition as the above.

INDUSTRIAL APPLICABILITY

As described above, the container for medical solution of this inventionis suitable to a parenteral solution bag for a closed system because ofits high-temperature resistance at autoclave sterilization, its superiortransparency, its highly reliable safety for human body, and itseasiness of draining the solution.

I claim:
 1. The container for a medical solution made from an organicpolymer having a port portion, a shoulder portion, and a flat bodyportion, characterized in that said container is made by blow molding,and the wall thickness in the side peripheral area and/or tail endperipheral area is thinner than the thickness in the central area ofsaid body portion.
 2. The container for a medical solution defined inclaim 1, wherein said organic polymer is polyolefin.
 3. The containerfor a medical solution defined in claim 1 wherein the Olson stiffness isnot greater than 4,000 kg/cm².
 4. The container for a medical solutiondefined in claim 1, wherein said wall thickness of the body portion isbetween 0.05 mm and 0.35 mm.
 5. The container for a medical solutiondefined in claim 1, wherein said organic polymer is primarily linear lowdensity polyethelene.
 6. The container for a medical solution defined inclaim 1, wherein the protruded portion is provided on said body portion.7. The container for a medical solution according to claim 1, whereinthe inside surface of said container is laminated with a materialdifferent from the material of which the container is made.